1. Field of the Invention
The present invention relates generally to chain saws, and to workbenches for safely using them. More particularly, the present invention relates to portable, folding workbenches adapted to be deployed to safely control chain saws for cutting and sawing diverse items in a safe and efficient manner.
2. Description of the Related Art
Conventional chain saws are powered by small gasoline or electric engines. Modern chain saws are in widespread use, particularly for cutting or trimming trees and large branches, or for cutting fireplace wood. The modern frequency and intensity of storms, including wind storms and tornadoes, and the resultant damages to trees and tree limbs, accentuates the value of a modern chain saw as a necessary household appliance. Chain saw use for cutting home firewood for heating has increased demonstrably as well.
Chain saws comprise a powered blade that revolves about a flat, elongated bar or “blade” that supports chain rotation. Numerous rigid, sharpened teeth supported by the revolving chain vigorously cut through workpieces such as branches, trees, logs and the like. Many conventional chain saws are lightweight and portable. Most chain saws include various types of guard structures designed to prevent the saw blade from inadvertently contacting and injuring the user. The handle by which the saw can be lifted and manipulated usually includes safety features such as automatic shut off switches. Various types of safety guards known in the art exist as well.
Despite the numerous safety advances engendered by modern saw designs, numerous dangers exist. In the first place, numerous users never read the saw's operating manual, or discern the numerous safety warnings printed in the manual. Modern chain saws typically require two hands to operate, but some users may try to hold workpieces in one hand while operating the saw with their other hand. Chain saw kickback is a well recognized danger. Kickback can unexpectedly occur when saw teeth impact with the workpiece during chain rotation, whereupon the saw may dangerously lurch backwardly towards the operator. Kickback often occurs when the blade of a chain saw strikes a metal object embedded in the workpiece. Unexpected saw movements may also occur when the operator completes a cut through a workpiece, and the saw suddenly frees itself and emerges from the workpiece as for example, when a log or branch is cut all the way through.
Chain saw weight is also a factor contributing to accidents. Although modern chain saws are designed to be lightweight, larger, heavier saws can become difficult to control, especially when operator fatigue develops. Weight makes it difficult to cut smaller workpieces that may not be mechanically anchored or tied down securely. This is especially true when the workpiece is not heavy enough to support itself, and must be supported during cutting by the foot or arm of the operator who may be standing in an unstable position. Operator fatigue can develop notwithstanding the supposed light weight of modern chain saws. Substantial physical exertion is required when cutting over large time periods. Fatigue develops as an operator continually bends over and straightens up, bearing the full weight of the saw.
Partly in effort to reduce accidents, and to simplify and streamline chain saw operation, various chain saw benches have evolved in the art. Usually such benches provide a stable horizontal surface for the workpiece, and means for bracing or securing the saw. Additional diverse tables including a variety of safety measures are also known in the art.
For example, U.S. Pat. No. 4,127,046 issued Nov. 28, 1978 discloses a portable bench for controlling a chain saw when sawing a workpiece. A saw blade guide plate projects through a slot defined in a mounting plate. The saw blade is protected by a guard pivotally secured to the mounting plate. A cradle frame that pivots about a horizontal axis releasably receives and clamps the mounting plate in a table sawing position when the chain saw is used. A pivotally supported turntable is positioned beneath and supports the pedestal. A workpiece-supporting table is positioned adjacent the cradle frame structure, pedestal and turntable, and has a substantially horizontal working surface located below the guide plate of the chain saw.
U.S. Pat. No. 4,210,049 issued Jul. 1, 1980 discloses a frame for supporting a chain saw. The foldable, tubular frame comprises a pair of elongated, spaced-apart legs supporting an elongated, rotatable shaft. A conventional chain saw is removably affixed to the shaft outside one end of the frame in a cantilever position. An elongated trough extends horizontally of the frame. The lower portion of the frame is anchored to avoid tipping. A control lever extends from the shaft alongside the saw, within the frame, so that the operator is protected from the saw chain.
U.S. Pat. No. 4,214,498 issued Jul. 29, 1980 discloses a control apparatus for supporting and operating a chain saw. A table for supports wood to be cut and an elongated actuating arm mounted on the table.
U.S. Pat. No. 4,215,612 issued Aug. 5, 1980 discloses another chain saw support. A supporting frame includes a bed for supporting a length of wood within the path of the saw blade. The saw blade is biased toward one side of the length of wood and a foot treadle is connected to the saw for overcoming the bias and moving the saw blade along the straight-line path to the other side of the length of wood.
U.S. Pat. No. 4,307,640 issued Dec. 29, 1981 discloses a supporting worktable for chain saws. The chain saw is swung about a fixed pivot to bring the chain of the saw into cutting engagement with a workpiece that is supported in an elevated position and restrained from movements. The table comprises a trough shaped top, and a pivoted and adjustable mounting plate that secures the saw.
U.S. Pat. No. 4,350,067 issued Sep. 21, 1982 discloses a chain saw mount for supporting and counterbalancing a portable power chain saw so that it may be manually swung by its handle between raised and lowered positions for cutting a workpiece supported by the apparatus.
U.S. Pat. No. 4,351,209 issued Sep. 28, 1982 discloses a chain saw bench having a first support member with an interdigital slot, a second support member having a cooperating slot for mating with the first support member to form a cross, and a top member hinged on a side parallel to its slot. The top member includes means for restraining the handle and body of the chain saw and positioning the saw to permit access to the top of said bar and chain. Remote control means are attached to the trigger of the saw. A pedal-type activator positioned remote from the saw activates the saw by pressure either from the operator's knee or from the operator's foot.
U.S. Pat. No. 4,606,252 issued Aug. 19, 1986 discloses apparatus used for supporting and controlling chain saws. The saw may be swung by its handle between raised and lowered positions, for cutting workpieces supported beneath.
U.S. Pat. No. 4,779,503 issued Oct. 25, 1988 discloses a portable stand for cutting timber. A vertical support mounted upon a base defines a functional area for resting work pieces to be cut. A second functional area for an operator to be located is defined on the opposite side of the vertical support. A beam mounted horizontally upon and parallel to the vertical support secures the chain saw mount is pivotally disposed upon the beam for removably receiving a chain saw, the chain saw mount adapted for movement along the axis of the beam. A clamp arm clamps onto timber disposed upon the first functional area for resting timber.
U.S. Pat. No. 7,159,496 issued Jan. 9, 2007 discloses a portable vise and saw including a vise with three attachment points. One attachment point is used to attach the vise to an existing support such as an existing horizontal rail, and another attachment point allows a saw to be mounted to the vise. A workpiece is mounted in the third attachment point. The saw is aligned with the workpiece so that the workpiece may be selectively cut at a desired length and angle. A measuring apparatus is also incorporated within the vise to allow an operator to set the saw to cut successive workpieces at the same lengths without having to remeasure each workpiece.
U.S. Pat. No. 7,159,499 issued Jan. 9, 2007 provides a support for portable band saws. A pivoting mount is maintained at a work surface. A bracket adjacent the mount receives a front portion of a blade housing structure of the portable saw. An extension bar supports a rear portion of the blade housing structure.
U.S. Pat. No. 7,581,477 issued Sep. 1, 2009 discloses a saw table and clamping mechanism for securing a work piece on the saw table. The clamping mechanism includes a clamping bar having a first end and a second end with a longitudinal axis defined therebetween. A first pivoting arm operatively connected to the clamping bar enables rotation about a pivot axis. A biasing device biases the clamping bar about the pivot axis to clamp the work piece between the clamping bar and a table base.
U.S. Pat. No. 7,661,346 issued Feb. 16, 2010 discloses a guide assembly for power tools with a rectilinear guide and a rotary guide slidably attached to the rectilinear guide with a post with axially opposed top and bottom ends. The rotary guide includes a knob provided with a rod with a first end directly attached to a bottom surface of the knob. The assembly further includes a mechanism for slidably attaching the rotary guide to the rectilinear guide and a mechanism for removably securing the rectilinear guide to a support surface.
U.S. Pat. No. 7,762,510 issued Jul. 27, 2010 discloses handsaw mounting assemblies and methods. A frame comprises a top portion configured to removably couple a saw motor assembly, and a bottom portion configured to fixedly couple a structure. A method of affixing a handsaw to a structure that includes removably coupling a motor assembly portion of the handsaw to a structure using an assembly.
U.S. Pat. No. Application No 2010/0122618 published May 20, 2010 discloses a folding base that converts a portable band saw into a fixed tool that may be used on a workbench. The mounting base has upper and lower cradles, the upper cradle folding down next to the lower cradle for storage. In use, the handle of the portable tool in placed in the upper and lower cradles, and held in position by a toggle clamp. The toggle clamp engages the hand tool trigger to maintain the tool in an operating condition.
U.S. Pat. No. Application No. 2010/0257743 published Oct. 14, 2010 discloses systems and methods for a chain saw safety device. A method comprises the steps of activating a chain saw, receiving a first acceleration value associated with acceleration of the chain saw, comparing the first acceleration value to a predetermined acceleration threshold, and deactivating the chain saw based on the comparison.
Despite all of the known advances in chain saw supports, known chain saw benches do not adequately combine ease of use with sufficient chain saw control to promote operator safety. Moreover, no known chain saw table providing the foregoing attributes is enabled to fold into a substantially flat stowage position.